In his speech, Obama referred to Missouri, which has made headlines for its increasing homicide rate and its loosening of gun control laws. He said:

"Meanwhile, since Missouri repealed a law requiring comprehensive background checks and purchase permits, gun deaths have increased to almost 50 percent higher than the national average. One study found, unsurprisingly, that criminals in Missouri now have easier access to guns."

Recent research by Johns Hopkins Bloomberg School of Public Health found that the state's repeal of certain licensing requirements for gun sellers corresponded with an 18 percent increase in firearm homicide rates statewide.

But what are Missouri's laws on firearms? Here's a short look:

No permit is required to buy rifles, shotguns or handguns

Owners do not have to register or be licensed to own rifles, shotguns or handguns.

Owners do need a permit to carry handguns but not shotguns or rifles.

Concealed carry requires a permit or endorsement. Missouri residents older than 19 who are U.S. citizens (or 18 and in the armed forces stationed in Missouri) can apply for such a permit. Applicants must submit to fingerprinting and background checks. Felons and those with one or more violent misdemeanors within a five-year period are ineligible.

A concealed carry permit is not required within a person's home or while hunting or traveling in a continuous journey in the state.

Concealed carry is not allowed in certain places, including courthouses, polling places, bars and lounges, and restaurants that earn less than half of their income from food sales.

People older than 21 can transport a firearm in the passenger compartment of a vehicle as long as it's lawfully possessed.

No local governments can regulate ownership, sale, use, licensing, registration or other controls regarding firearms.

Antique firearms are exempt from permit requirements for transfer of concealable firearms.

An individual cannot own, sell or transport machine guns without a federal license.

It is illegal to own, transport or sell a rifle with less than a 16-inch barrel, a shotgun with less than an 18-inch barrel, a rifle or shotgun less than 26-inches long, silencers, switchblades or explosive bullets.

It is illegal to sell a firearm to someone who cannot legally have one.

It is illegal to bring a firearm or weapon into a school, onto a school bus or to a school-sanctioned activity. This doesn't apply to those with a concealed carry permit and permission from school officials.

It is illegal to deface a firearm or own a defaced firearm.

It is illegal to display a weapon in an angry or threatening manner.

Records of permits to obtain a concealed weapon are closed to the public.

A Firearm Owner Identification (FOID) card is required to purchase and own rifles, shotguns and handguns.

FOID cards can be obtained by Illinois residents 21 years old and older who have not been convicted of a felony, are not addicted to narcotics and have not been a patient in a mental-health facility in the last five years, among other restrictions.

Applicants under 21 with the consent of a parent who is not prohibited from having a FOID card and with no misdemeanors (other than traffic offenses) can also get a FOID card.

No permits are required to carry rifles and shotguns, but a FOID card is required to carry a handgun.

No one under 18 can possess a handgun or a concealable firearm.

Firearms do not have to be registered.

There are no castle doctrine laws.

Illinois has a partial ban on carrying at restaurants.

Antique firearms are exempt from purchasing regulations.

Concealed carry licenses are required. Residents 21 and older with a valid FOID card can apply. Applicants must submit to fingerprinting and undergo 16 hours of training. Applicants cannot have pleaded guilty to two or more DUI violations or a misdemeanor involving threat of physical force or violence in the last five years, among other disqualifications.

It is illegal to carry or possess a firearm in a vehicle or concealed about the person without a license, except on one's own land or house or for licensed hunters, trappers and fishermen while engaged in their activity. Firearms broken down into parts, not immediately accessible or unloaded and enclosed in a case or box are also exempt.

Local governments may not enact ordinances on guns; it is now the authority of the state.

The vehicles of people with valid FOID cards are considered "safe haven" for transporting firearms.

Firearms can be stored in the glove compartment as long as the vehicle or container is locked and the firearm is out of plain view.

Carrying firearms, including concealed carry, is prohibited at schools, courthouses, libraries, government buildings and public parks, among other places. Three violations will result in permanent revocation of a license.

It's illegal to have a rifle with less than a 16-inch barrel, a shotgun with a barrel less than 18 inches, or any rifle or shotgun weapon less than 26 inches.

It is illegal to have a firearm at any place selling alcohol or at certain public gatherings, such as where admission is charged.

A minor can possess a firearm or ammunition without a FOID card while under the control of a parent or guardian with a FOID.

A person with a FOID card can loan a gun to an individual with a card, if the gun is being used at a range and under supervision.

It is illegal to have firearms or ammunition on school grounds.

Buyers must show a FOID card to buy firearms or ammunition.

Firearms sellers must withhold delivery of any handgun for 72 hours, and any rifle or shotgun for 24 hours, after purchase. Records of transfers must be held for 10 years.

Gun owners privately selling firearms at gun shows must make sure the buyer has a FOID card and undergoes a background check.

It is illegal to buy, sell, possess or carry machine guns or parts that could create a machine gun.

It is illegal to alter or erase a firearm's serial number, maker's name or identifying marks or have a weapon with such alterations.

For more information on state gun laws, read the Brady Campaign to Prevent Gun Violence's 2013 State Scorecard. The pro-gun control organization ranks Illinois as one of the top 10 states with the strongest gun laws. It gives Illinois gun laws an overall grade of B and Missouri an F.

In 2015, on average there is more than one mass shooting per day in the United States—and the impact of that is felt across the country. From the terror attacks in Charleston, Paris, Colorado Springs and San Bernardino to shootings closer to home, it is hard for the topic to stay off the minds of Americans these days.

The past year was a landmark one for many legal issues—both nationally and locally. On Thursday’s “St. Louis on the Air,” our monthly Legal Roundtable convened to discuss the legal decisions (or lack thereof) which had the most impact on 2015. They also looked ahead to 2016.